Abstract: Reliable vehicle start is necessary to support mission success, especially for response time. At Department of Defense installations in cold regions, vehicles using rechargeable battery and starter technologies have significant issues starting in the cold. Ultracapacitor engine start modules (ESMs) are an alternate technology to rechargeable lead-acid or lithium-ion batteries. The project develops a performance baseline for the ESM used in the M1126 Stryker Combat Vehicle under cold conditions. To test the performance of the ESMs in a cold room, a mechanical load system was constructed to replicate the load of starting a Stryker engine and instrumented with sensors to monitor parameters such as voltage, torque, and temperature. The ESMs were tested with the load system at temperatures from 24°C to −40°C. The results of the tests showed that there was some degradation of the ultracapacitor’s performance at the colder temperatures, which was expected, but no permanent damage. This work provides a test protocol and capability to evaluate next-generation vehicle battery systems for cold regions applications. Additionally, the ESM cold performance data establish a baseline to compare next-generation vehicle battery storage systems and to support cold regions missions and identify potential performance requirements for future vehicle battery system acquisition.